Summary

Rationale: Axial spondyloarthritis (axSpA) is an inflammatory back pain disorder affecting
up to 24% of young chronic low back pain (CLBP) patients. For general practitioners (GPs) it
is difficult to distinguish axSpA patients in the large amount of CLBP patients. In previous
studies a referral rule for axSpA applicable in CLBP patients was developed and validated.
The next step is to investigate the impact of the referral rule in daily practice. This
impact analysis will test if the referral rule will be beneficial or harmful.

Objective: To evaluate the clinical impact of a referral rule in young patients presenting
at the general practitioners with chronic low back pain, who are at risk for axSpA, compared
to usual care.

Intervention (if applicable): GPs are randomized in clusters either to use directly the
referral rule or use the referral rule after 4 months. The referral rule consists out of
four variables, a positive ASAS inflammatory back pain questionnaire, a positive family
history for spondyloarthritis, a good reaction to NSAIDs (non-steroidal anti-inflammatory
drugs) and back pain duration longer than 5 years. If at least two out of four variables are
present a referral to the rheumatologist is advised.

Main study parameters/endpoints: The primary outcome is a change in the Roland Morris
Disability Questionnaire (RMDQ) compared to baseline in the CLBP patients with or without
use of the referral model.

Secondary parameters: Quality of life measurements, cost-effectiveness, pain and fatigue and
referral to rheumatologist and diagnosis of axSpA.

Nature and extent of the burden and risks associated with participation, benefit and group
relatedness:

The burden and risks associated with participation are minimal. No medical intervention is
taken place. If the GP of the patients is randomized to the referral model, the patient is
checked for the risk of axial spondyloarthritis, by the non-invasive referral model. If the
referral model is positive a referral to the rheumatologist is advised. Is the GP is
randomized to the 'usual care' there is no difference in the treatment of low back pain than
nowadays. A GP is still allowed to treat the CLBP patients optimal and a referral to the
rheumatologist is allowed but not actively advised.

All participating CLBP patients are asked to fill several questionnaires at four different
time points, at baseline, after 12 months and after 24 months. In total there are 8
questionnaires and four separate questions. The questionnaire are designed to fill out by
the patient themselves. The total time to fill in the questionnaire is estimated to be 30
minutes.

The benefits of the study are:

- For the CLBP patients, up to 24% of the back pain complaints are caused by axSpA, but
the GPs are not (yet) aware of this disease. When a CLBP patient is participating in
this study, the chance of having axSpA as cause for the back pain is investigated. This
a benefit for a CLBP patients since there is effective treatment for axSpA.

- For the GP it is very difficult to distinguish an axSpA patients in the large amount of
CLBP patients. If it appears that the validated referral rule has an impact on CLBP and
GPs, the next step will be implementation of this referral model in daily practice and
it will become a helpful tool for the GP.

- For the society, CLBP is a great socioeconomic burden for the society. When one of the
causes for CLBP, namely axSpA is diagnosed and treated in an earlier stage this will
lead to a decreased sick leave because of back pain and is therefore potentially
cost-effective.

Study Design

GP are randomized in clusters either to use or not to use the CaFaSpA referral model. The CaFaSpA referral models consists out of four variables, a positive ASAS IBP questionnaire, a positive family history for SpA, a good reaction to NSAIDs and back pain duration longer than 5 years. If at least two out of four variables are present a referral to the rheumatologist is advised.

applying a referral model

GP are randomized in clusters either to use or not to use the CaFaSpA referral model. The CaFaSpA referral models consists out of four variables, a positive ASAS IBP questionnaire, a positive family history for SpA, a good reaction to NSAIDs and back pain duration longer than 5 years. If at least two out of four variables are present a referral to the rheumatologist is advised.

Primary Outcomes

Measure

The primary outcome is a change in the Roland Morris Disability Questionnaire (RMDQ) compared to baseline in the CLBP patients with or without use of the referral model.